A transmission system for a vehicle is suitably configured to deliver improved power transmitting efficiency, and improved fuel efficiency. Transmission mechanisms may include a manual transmission, a conventional stepped automatic transmission, a continuously variable transmission, a double clutch transmission, or other type of vehicle transmission. Such transmissions are typically used with conventional gasoline or diesel engine systems.
As newer, more fuel efficient vehicles are being developed there is an ever changing need for more versatile lubricating and power transmission fluids. Furthermore, different manufacturers have different criteria or specifications for the performance of the transmission fluids that are suitable for use in their vehicle's transmissions. In a transmission fluid, friction durablity and anti-shudder performance are important characteristics of the fluid. However, additives that improve one property of the fluid may be detrimental to another property of the fluid. For example, increasing the amount of friction modifier in a transmission fluid in order to improve the friction durability of the fluid may detrimentally increase the Brookfield viscosity (BV) of the fluid an undesirable amount so that the fluid no longer meets the required low temperature viscosity limits. Hence, there is a need for a single fluid that can be adapted for use in a variety of vehicle types and manufacturers, yet meet the manufacturer's specifications.
In view of the foregoing, embodiments of the disclosure provide a lubricant composition, a multi-vehicle transmission fluid containing the lubricant composition, and a method for making a transmission fluid including the lubricant composition. The lubricant composition includes a) a base oil; b) 2,5-dimercapto-1,3,4-thiadiazole (DMTD), a derivative of DMTD, or mixtures thereof; and c) a friction modifier. The friction modifier is made by reacting an olefin containing at least 40% by weight C10-C36 vinylidene olefin with maleic acid, anhydride, or ester to provide a first reaction product, and aminating the first reaction product with an effective amount of a compound containing basic nitrogen to provide the friction modifier. The C10-C36 vinylidene olefin is represented by the following formula:
wherein Rc and Rd are independently a (C3-C15) alkyl, cycloalkyl or cycloalkenyl.
Another embodiment of the disclosure provides a transmission for a vehicle containing a lubricating fluid. The lubricating fluid includes a) a base oil; b) 2,5-dimercapto-1,3,4-thiadiazole (DMTD), a derivative of DMTD, or mixtures thereof; and c) a friction modifier. The friction modifier is made by reacting an olefin containing at least 40% by weight of a C10-C36 vinylidene olefin with maleic acid, anhydride, or ester to provide a first reaction product, and aminating the first reaction product with an effective amount of a compound containing basic nitrogen to provide a the friction modifier. The C10-C36 vinylidene olefin is represented by the following formula:
wherein Rc and Rd are independently a (C3-C15) alkyl, cycloalkyl or cycloalkenyl. The lubricating fluid for the transmission may be prepared using the lubricant composition or the transmission fluid of the disclosed embodiments, thus it may comprise, or be identical with, the lubricant composition or transmission fluid.
Other embodiments of the disclosure provide a transmission fluid and a method for providing a specific multi-vehicle transmission fluid of the disclosed embodiments. The method includes blending an oil of lubricating viscosity with: i) from about 100 to about 2000 ppm by weight 2,5-dimercapto-1,3,4-thiadiazole (DMTD), a derivative of DMTD, or mixtures thereof in terms of sulfur content of the transmission fluid derived from component (i); and ii) from about 50 to about 800 ppm friction modifier in terms of nitrogen content based on a total weight of the transmission fluid of a friction modifier. The friction modifier is made by reacting an olefin containing at least 40% by weight of a C10-C36 vinylidene olefin with maleic acid, anhydride, or ester to provide a first reaction product, and aminating the first reaction product with an effective amount of a compound containing basic nitrogen to provide the friction modifier. The C10-C36 vinylidene olefin is represented by the following formula:
wherein Rc and Rd are independently a (C3-C15) alkyl, cycloalkyl or cycloalkenyl.
An advantage of the compositions and methods of the disclosure is that the fluids described herein containing the DMTD and the friction modifier are capable of providing the fluid with at least one, and preferably all three, of: reduced low temperature Brookfield viscosity, improved yellow metal protection and superior corrosion protection and improved friction durability. Specifically, this may be exemplified by at least one, and preferably all three, of: a low temperature Brookfield viscosity (BV) at −40° C. of less than 14,000 centipoise (cp), a weight percent lead loss in an aluminum beaker oxidation test of less than 0.5 wt. %, and a friction durability in a low velocity friction apparatus at 40° C. of greater than 300 hours. In addition, the compositions and methods of the disclosure are capable of providing exceptional high static friction performance in an SAE No. 2 friction rig while also maintaining the Brookfield, LVFA, and lead loss performance described above.
Additional features and advantages of the disclosure may be set forth in part in the description which follows, and/or may be learned by practice of the disclosure. The features and advantages of the disclosure may be further realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.